This application requests core support (P30) to establish a Center for Early Detection, Prevention, and Treatment of HIV (ED-PaTH) in Los Angeles (LA) LA is the second largest AIDS epicenter in the U.S.; its population is highly diverse; and the county is spread over 419 miles. Researchers, community members, service providers, and governmental agencies need to be linked in LA; therefore, an interdisciplinary group (43% minority investigators) has formed a Center in order to enhance understanding of emerging scientific breakthroughs in HIV research and to promote early detection, effective prevention, and treatment programs for HIV at the societal, community, and individual levels. To accomplish this mission, four Cores will support the design, implementation, and evaluation of existing funded projects and assist in the development of new research protocols focused on communities, systems-of-care, service providers, and individuals at risk. Specifically, in the areas of early HIV detection, prevention, and treatment, we will have: (1) an Administrative Core to identify strategies for addressing policy issues related to emerging new technologies and findings by coordinating examination of issues in their broader contexts within multi-layered, multi-disciplinary teams; (2) an Assessment Core to develop multi- method reliable and valid assessment measures that integrate biological and psychosocial indices and that are sensitive to ethnic, gender, and socioeconomic influences; 3) an Intervention Core to examine the theories, designs, delivery, and quality of HIV-related services and dissemination of successful programs; and (4) an Evaluation Core to develop innovative biostatistical analytic strategies, assist community-based program evaluation, and enhance our understanding of cost-effectiveness. These Cores will enhance researchers' and the communities' awareness, skills, resources, and capacities to generate high quality HIV research and training. Each Core will deliver consultation, technical assistance, enhance communication within their area of expertise, and participate in training activities. The broader HIV community in LA will benefit from the following aspects of the Center a strategic planning process involving researcher-community partners, an Annual Policy Forum, routine updates and bibliographic support, consultation from the Cores, colloquia, the existence of an infrastructure to foster collaborations and improve the quality of our science, and increased training opportunities for faculty and students interested in the area of HIV. The Center, aimed primarily at social and behavioral HIV research, is proposed, anticipating a complementary application for a Center for AIDS Research (CFAR) that focuses on clinical and basic science HIV-related research.